This invention relates to a frame assembly for holding a stretchable web such as an artist's canvas and the like, and more particularly to a device for selectively adjusting the tension of the stretchable web.
Artist's canvases have a tendency to expand and contract with changes of temperature and relative humidity causing cleavage, losses in paint film and the formation of draws along the edges and corners of the painting. In an effort to alleviate this problem, serrated stretcher frames of the type found in U.S. Pat. No. 3,127,695 and expandable stretcher frames of the type found in U.S. Pat. No. 3,625,274 have been provided. These stretcher frames, however, do not permit pinpoint stretching or slackening of certain sections of the canvas without disturbing other sections of the canvas. Furthermore, expandable stretcher frames change their dimensions, losing dimensional stability, during stretching and expansion making it difficult to remount a painting in the original frame.
Non-expandable frames of the type found in U.S. Pat. Nos. 3,126,332 and 3,485,165 have been provided for one-sided stretching of sifting cloths and silk-screens, without disturbing other sides of the web and are more desirable than expandable frames, because they remain dimensionally stable so that the outer dimensions of the frame remained unchanged during stretching. These non-expandable frames, however, do not permit sections along one side of the web to be stretched or loosened, without concomitantly stretching or loosening other sections along the same side of the web, which might not need any alterations and could be damaged by any expansion or contraction. Stated in other terms, these prior art non-expandable frames do not permit localized stretching and contraction, and like the expandable frames do not permit the traditional method of stretching, whereby the canvas is stretched from the center side first and alternatively rotated and stretched left and right for even fabric stretching.
It is therefore an object of this invention to provide an improved dimensionally stable non-expandable stretcher frame which permits traditional canvas stretching and subsequent localized web stretching and contraction with a predetermined number of selectively spaced clamps.
The foregoing and other objects and advantages will be apparent from the following description and appended claims taken in conjuntion with the accompanying drawings.